1. Technical Field
The present invention relates to a microfluidic system, sample analysis device, and target substance detection/measurement method used mainly for detecting reaction of a biological sample.
2. Related Art
A method for performing chemical analysis, chemical synthesis, or biotechnology-related analysis by using a microfluidic chip composed of a glass plate having a fine flow path on its surface has been attracting attention. In a microfluidic chip, also called“micro total analytical system” (micro TAS), or “Lab-on-a chip,” etc., the required amount for a sample is smaller, the reaction time shorter, and the amount of waste smaller than in conventional devices. Because of those advantages, application in various fields, such as diagnosis, onsite analysis of environments or foods, is expected.
Analysis using a microfluidic chip needs a means for stably introducing a sample solution to a fine flow path while controlling the injection speed to make samples react by mixing sample solutions in the fine flow path in the chip, and detect that reaction, and a micropump, or a syringe pump, or something similar is used as that means.
JP-A-2005-227250 discloses a method for stopping and performing solution transfer by connecting a pump and a fine flow path in a microchip.
In the method disclosed in JP-A-2005-227250, the microchip, valve, and solution transfer pump are connected via capillaries, as shown in FIG. 1. Their connecting parts have to be joined to each other with a silicone tube or the like, but sometimes bubbles enter from the joint and prevent the flow of the sample solution. Moreover, because the volume in the capillaries is dead volume, the reaction time delays and the sample solution is wasted. Furthermore, the whole apparatus becomes large when capillaries are used for connection, and as a result, the advantage of the compact structure of the microfluidic system cannot be fully utilized.